RESUMO
Polarized structured nitride semiconductors are attractive due to their unique and environment-friendly electronic properties. The stability, ferroelectricity and photocatalytic and photovoltaic properties of super-wurtzite Mg2XN3 (X = Bi, Mo, Nb, Sb, Ta, Tc and W) were determined based on first principles calculations in this study. The calculated results indicate that Mg2XN3 (X = Sb, Ta, Bi and Nb) are stable polar nitrides by phonon frequencies, elastic coefficients and ferroelectric analysis. Mg2XN3 (X = Sb, Ta and Nb) with large ferroelectric polarization strength could absorb ultraviolet light to promote photocatalytic water splitting for hydrogen production. Mg2BiN3 is a new excellent photovoltaic candidate due to its ideal energy band, high electron mobility, high absorption coefficient and large ferroelectric polarization strength.
RESUMO
One new flavonoid glycoside (1) and one new triterpenoid cinnamate (2) were isolated from Nervilia fordii. The structures of 1 and 2 were determined by extensive NMR and HRESIMS to be 7-O-ß-d-glucopyranosylapigenin-8-C-ß-d-glucopyranosyl-(1 â 2)-ß-d-glucopyranoside and 24(S/ß)-dihydrocycloeucalenol-3-(Z)-p-hydroxycinnamate, respectively.
Assuntos
Cinamatos/isolamento & purificação , Medicamentos de Ervas Chinesas/isolamento & purificação , Flavonoides/isolamento & purificação , Glicosídeos/isolamento & purificação , Orchidaceae/química , Plantas Medicinais/química , Triterpenos/isolamento & purificação , Cinamatos/química , Medicamentos de Ervas Chinesas/química , Flavonoides/química , Glicosídeos/química , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Folhas de Planta/química , Estereoisomerismo , Triterpenos/químicaRESUMO
From the water-soluble extract of the aerial part of herbal plant Nervilia fordii, three new cycloartane glycosides, named as nervisides A (1), B (2), and C (3), were isolated. Their structures were elucidated through a combination of spectroscopic analysis and hydrolysis. At the same time, the new compounds were tested for their cytotoxicities in vitro against human tumor cell lines (CNE, Hep-2, and HepG2) using MTT method.